Spinifexbird (Eremiornis carteri)

As its name suggests, the spinifexbird is closely associated with areas of spinifex grass, in which it locates prey and builds its nest.

The densest population of spinifexbirds is known to be on Barrow Island, off the coast of Western Australia, where it is the most abundant bird species.

Although the spinifexbird feeds primarily on grasshoppers, beetles and other insects, it is also known to eat seeds.

Bush fires and introduced predators are thought to be the main threats facing the spinifexbird.

The spinifexbird is classified as Least Concern (LC) on the IUCN Red List (1).

Also known as Carter’s desertbird (2), the spinifexbird (Eremiornis carteri) is named after Thomas Carter, an English ornithologist and explorer in the late 19th and early 20th centuries (3).

The spinifexbird is a warbler with a rich brown or reddish-brown cap (4) (5), which shades to greyish on the sides of the head (2). The nape, shoulders, back, rump and uppertail-coverts are all greyish-brown to warm brown (2), while the dark brown wings have wide, paler brown fringes, giving them a streaked appearance (2) (4) (5). The spinifexbird has light greyish-buff or buffy-white underparts (2) (5), which change to a warmer cinnamon-buff on the flanks and undertail-coverts (2). The long, graduated tail is dark brown or blackish-brown with a pale buffy tip (2) (4) (5).

Both the legs and the bill of the spinifexbird are greyish-pink, while the eyes are dark brown (2). Male and female spinifexbirds are similar in appearance (2) (4) (5), and the juvenile bird resembles the adult except for being slightly streaked and having brighter pink legs (2).

The spinifexbird usually delivers its distinctive, high-pitched song from a large hummock of spinifex grass or from the top of an acacia bush. The loud song, which varies markedly between individuals, is described as a repetitive ‘cheerywheat’ or an abbreviated ‘cheerit’ which is repeated approximately every three seconds and ends in a descending ‘cheeroo’. The spinifexbird’s alarm and contact calls include a sharp ‘kit’ and a harsh, scolding ‘chut-chut’ (2).

The spinifexbird is native to Australia (2) (4), and can be found in the country’s arid interior (6) (7). It has a patchy distribution from coastal Western Australia to north-western and central Queensland (2) (7), and also occurs on some offshore islands (2) (5). The densest spinifexbird population is known to be on Barrow Island, off the coast of Western Australia, where it is the most abundant bird species (2). However, the spinifexbird has become locally extinct on the Montebello Islands (8).

A specialist of arid environments, the spinifexbird is found in a variety of habitats, including dry scrub, grassland and the rocky hillsides of upland deserts (2) (4) (7). As its name suggests, this species is always associated with stands of spinifex grass (2) (5) (6) (7). Such preferred areas of habitat are usually found alongside watercourses (2) (4).

A largely solitary bird (4), the spinifexbird is thought to be non-migratory (2) (4), although the discovery of a new population in central Queensland in 2002 indicates that there is a possibility that this species could be at least partially nomadic (2).

The spinifexbird primarily feeds on small invertebrates, including grasshoppers (Orthoptera) and small beetles (Coleoptera). In certain parts of its range, such as Barrow Island, the spinifexbird appears to be almost entirely insectivorous (2), but in other areas it is also known to eat a variety of seeds (2) (4), including those of the mulla-mulla (Ptilotus species). This species typically feeds alone or in family parties, hopping along with its tail raised, pecking at insects on the ground or within sharp tussocks of spinifex grass (2).

As well as being prime areas for hunting invertebrate prey, dense clumps of spinifex grass provide the spinifexbird with cover if disturbed. To check if danger has passed, this species usually clambers to the top of a grass tussock, chattering nervously (2). The spinifexbird is not a strong flier, fluttering weakly, straight and low, with its tail drooping (2) (4). It is also known to drop to the ground and run for cover (2).

The majority of breeding in the spinifexbird occurs between August and November (2) (4), but the sudden onset of heavy rainfall can trigger breeding activity outside of this period (2). There is little information on the breeding biology of the spinifexbird, but its nest is known to be a shallow cup of woven grasses, built in a dense grass tussock close to the ground and lined with fine rootlets. The female typically lays a clutch of two eggs (2) (4), and incubates them alone. There is no available information on incubation and nestling periods in this species, but the female is thought to be able to rear two broods in good seasons (2).

While the spinifexbird has an extremely large range (9) and is not considered to be globally threatened (2) (4), this species does face several threats and is thought to be decreasing in certain areas. Such population declines are believed to be the result of local extinctions due to bush fires and the presence of introduced predators (9). Some island populations of the spinifexbird have become all but exterminated as a result of predation by feral cats (2).

In certain parts of the spinifexbird’s range, it is hoped that cat eradication programmes will solve the issue of predation by feral cats (2). There are plans to eradicate both feral cats and black rats (Rattus rattus) from the Montebello Islands, where the spinifexbird has become locally extinct, to enable the successful reintroduction of this specialist bird (8).

Sibley, C.G. and Monroe Jr, B. (1991) Distribution and Taxonomy of Birds of the World. Yale University Press, Connecticut.

Morris, K.D. (2002) The eradication of the black rat (Rattus rattus) on Barrow and adjacent islands off the north-west coast of Western Australia. In: Veitch, C.R. and Clout, M.N. (Eds.) Turning the Tide: The Eradication of Invasive Species.Proceedings of the International Conference on Eradication of Island Invasives. IUCN Species Survival Commission, IUCN, Gland, Switzerland and Cambridge, UK.